Cryptainer LE is a freeware utility from Cypherix. It is a 128 bit disk encryption software that is a “miniature” version of Cryptainer PE and Cryptainer. It creates encrypted containers (vaults) of upto 25 MB each to store any type of data. You can encrypt files and folders by simply dragging and dropping them into this vault. Additionally, it lets you create secure e-mail files that you can send to anyone. Cryptainer LE includes a ‘Mobile’ feature, which allows it to encrypt all media (including, USB, CD ROM etc). It works on all 32 bit versions of Windows.

“Cryptainer LE. Free encryption software”
No, it’s free of cost. There is no way to know how strong the encryption really is or if there are any backdoors built in. TThey are using BlowFish encryption algo, but no reason to trust they implemented it correctly. Moreover, blowfish isn’t invisable — which means that you can still tell there is something encrypted which is grounds to be arrested in the UK and other countries. Works only in Windows.

GPG (formerly known as PGP)
Is based on RSA, and is open source. It’s free to download any version of it, even after two years. It’s been peer reviewed by the open source community so the likelihood of back doors is a lot smaller. It allows encryption to another specific person and allows for real electronic signatures. It, however, also generates output that is very clearly encrypted, and can land you in jail in the UK. Works on Linux, Mac and OSX. There is also at least a Java implementation under works, but I don’t know it’s progress.

TrueCrypt
Opensource, free to use modify and distrute just as GPG is. Works on Linux and Windows and there is an OSX version in the works. TrueCrypt supports AES, Serpent and Twofish encryption.
TrueCrypt uses stenography to hide volumes for plausible denyibility.

If your really interested in cryptography you should check GPG and TrueCrypt out.